Sometimes it's hard to notice the passing of time. It's hard to distinguish one day from another. Things just happen and then suddenly its already another day.
I was certain that I wrote already today. I had a clear memory of writing. But somehow I forgot a big portion of what happened in between. It was yesterday. And I do remember all the other things that happened yesterday and today as well. I just couldn't distinguish the relation between those events.
All those things just happened. In certain order I'm sure. But without thinking about it I can't outright tell the order. Or even was it yesterday or today. I need to go through the day in my mind to put those events in a timeline. Think about what happened before or after something.
It's a good thing I'm tracking all the important things I need to do every day. Otherwise I might miss something important thinking I have already done it today. Or forget to do something I was supposed to do on a particular date.
This is also another thing why routines are important. Those make sure things get done every day without relying on memory alone to make sure they get done.